Fluid injection devices, such as insulin pens, are relatively well known in the medical arts, for use in delivering or dispensing an agent, such as insulin or another prescribed medication, to a patient. Typical insulin pens must be physically manipulated by a user to configure a desired dosage, with that desired dosage often being manually calculated or determined by the user. However, the amount of manual interaction required poses a risk of human error, for example, when manually determining the proper dosage amount and/or when manually operating the pen to self-administer that desired dosage, and such risks may be further exacerbated if the user is experiencing a hypoglycemic or hyperglycemic event. Accordingly, it is desirable to provide injection pens that are capable of accurately and reliably delivering a specific dosage in a simplified manner that reduces the workload on the user.